This is some kind of misunderstanding that the virus bounces off vaccinated people. No, the science and data say that vaccinated people have a MUCH easier time with the virus, most of the time avoiding hospitalization and /or death.
So if he/she was hospitalized for 10 days, he/she probably would have died without the vaccine. I take 10 hospital days over death.
Also, vaccination is not 100% efficacy. Thus, there will be breakthrough infections.
In addition, the Delta Variant may have "lowered" the efficacy of the vaccines.
wrbtrader